This invention relates generally to the splicing together of a small wire and a large wire and more particularly to the termination of a small fragile wire, such as a magnet wire, and a larger lead-in wire, particularly of the stranded wire type.
There are many applications where it is necessary to connect together a very small wire, such as a magnet wire which is commonly used in small electric motors, and a larger lead-in wire, which frequently is of the stranded wire type. Such applications occur, for example, in synchronous motors employed in electric clocks and also in the new type ignition systems employed in the automotive industry which utilize a fine wire wound upon a bobbin which must be connected to a larger lead-in wire. While in some of these applications the larger lead-in wire is solid copper, many of the larger lead-in wires are of the stranded wire type.
In the prior art one common way of connecting a magnet wire to a larger lead-in wire is to lay both wires side-by-side within the barrel of a terminal which had serrations therein running substantially circumferentially around the terminal barrel. When the barrel is crimped shut, the magnet wire and the larger wire are forced together, with the magnet wire hopefully being forced into the serrations within the terminal barrel thereby causing the magnet wire to become elongated and break the thin shellac or plastic insulation which is commonly coated on magnet wires.
However, the foregoing method of splicing has certain disadvantages whether the larger wire is a solid conductor or a stranded wire. In the case where the larger wire is a solid conductor, the fine, fragile magnet wire is trapped between the relatively hard surfaces of the copper conductor and the metal serrations of the terminal barrel with the result that breakage of the magnet wire often occurs, or serious weakening of the wire might occur, with actual breakage happening later while the circuit is in actual use.
In those cases where the larger wire is of the stranded type, the magnet wire frequently is simply forced into the maze of stranded wires with the result that the insulation coating thereon is never broken and electrical contact between the magnet wire and the stranded wire does not occur.
A more recent means of connecting magnet wires to a larger wire, elastomeric substances are placed in the serrated barrel along with the magnet wire. When the barrel is crimped, the resilient and relatively soft elastomeric material will force the magnet wire into the serrations in the barrel, thereby stretching the magnet wire and breaking the insulation thereon so that the copper underneath can and will make good electrical contact with the serrated portion of the terminal barrel. A larger wire can then be connected to another portion of the terminal in a conventional manner.
While the last-mentioned method of connecting a magnet wire to a large wire works very well and is believed to be generally superior to any other known method for certain applications, it does require a specially prepared terminal barrel containing a piece of elastomeric material and a separate means for making contact with a larger wire. The electrical contact between the magnet wire and the larger wire occurs through the metal body of the terminal.